Method for manufacturing air-stable sulfide solid electrolyte, sulfide solid electrolyte manufactured thereby, and all-solid-state battery comprising the same

Air-stable metal-substituted sulfide solid electrolyte synthesized via wet process using amine-thiol co-solvent

This technology enhances air stability and ionic conductivity by wet-synthesizing metal-substituted sulfide solid electrolytes. It involves dissolving metal chalcogenides in a co-solvent mixture of amine and thiol, followed by a reaction with lithium-based and sulfide-based precursors.

Conventional wet synthesis methods struggle with poor raw material solubility, making it difficult to control the composition of the solid electrolyte. Furthermore, they suffer from limited air stability due to the generation of hydrogen sulfide (H2S) gas upon reaction with moisture.

This technology utilizes a co-solvent of 1,2-ethylenediamine and 1,2-ethanedithiol in a 7–12:1 volume ratio to fully dissolve metal chalcogenides like SnS2. By reacting this with precursors and performing vacuum heat treatment, it produces solid electrolytes substituted with elements such as Sn, Sb, and Zn, resulting in a dense structure and superior air stability. This technology can be applied to mass production processes for all-solid-state batteries that require reduced dry room management, as well as automotive all-solid-state cells, improving both handling safety and process yield by minimizing hydrogen sulfide generation upon air exposure.

‍

‍

Key Features:

• Step of preparing a precursor dispersion by dispersing lithium-based and sulfide-based precursors in tetrahydrofuran at a weight ratio of 1:1.5 to 3.5
• Co-solvent with a boiling point of 110 to 200 °C, consisting of 1,2-ethylenediamine and 1,2-ethanedithiol mixed in a 7 to 12:1 volume ratio
• Step of preparing a reactant by mixing the co-solvent, metal chalcogenide (SnS2 or Sb2S5), and the precursor dispersion
• Step of heat-treating the reactant in a vacuum to produce a metal-substituted sulfide solid electrolyte, such as Li3.2P0.8Sn0.2S4

‍

This invention was developed with support from the Ministry of Trade, Industry and Energy for the development of high-voltage battery systems for electric vehicles capable of ultra-fast charging in approximately one minute.

‍